In Lear, Inc. v. Adkins (1968), the U.S Supreme Court ruled that a licensee in a patent agreement is not required to continue paying royalties if they can prove that the patent is invalid. The case involved an inventor named John Adkins who had developed and patented a new type of gyroscope design which he licensed to Lear, Inc., an aviation company. Later on, Lear challenged the validity of Adkin's patent and stopped paying him royalties for it while continuing to use his invention in their products. When Adkins sued for breach of contract, lower courts sided with him based on the doctrine of "licensee estoppel," which prevented licensees from challenging patents they were licensing. However, upon reaching the Supreme Court, this ruling was overturned as it found that public interest in maintaining free competition within markets outweighed any contractual obligations between parties under licensee estoppel doctrine; thus allowing licensees like Lear to challenge potentially invalid patents without fear of breaching contracts or being held liable for unpaid royalties.

In the dissenting opinion for Lear, Inc. v. Adkins, Justice John Marshall Harlan II argued that the majority's decision undermined patent law and threatened to destabilize contractual relationships between inventors and manufacturers. He contended that by allowing Lear to challenge Adkins' patent validity after having benefited from its use, the Court was effectively encouraging bad faith agreements where companies could reap benefits of a patented invention while retaining an option to avoid payment if they later decide it is in their interest. This would discourage inventors from sharing their innovations with manufacturers due to fear of not being compensated fairly or at all. Furthermore, he expressed concern over how this ruling might affect future licensing agreements as well as existing ones retroactively; potentially leading to widespread litigation and uncertainty within industry sectors reliant on such arrangements.